An outbreak of a rare Salmonella strain in which chocolate-hazelnut spread is the likely cause has sickened 40 people in Germany, resulting in one death. Children and adolescents, mostly from Eastern Germany, have been primarily affected, according to the Robert Koch Institute (RKI).

RKI is investigating the outbreak in collaboration with other public health authorities in Germany.

Outbreak caused by rare serovar

The outbreak strain, Salmonella Bochum, is described as “extremely rare” by RKI, with 0–4 reported cases per year in Germany. No infections caused by this pathogen were recorded in Germany between 2019 and 2024. During the same period, the European Center for Disease Prevention and Control (ECDC) reported a total of 12 cases across EU/EEA countries. There is no information in the literature regarding the reservoir or global distribution of S. Bochum.

The outbreak strain was found to be susceptible to all antimicrobial substances tested by the National Reference Center (NRC) for Salmonella and other bacterial enteric pathogens.

Outbreak epidemiology

As of April 14, a total of 40 cases have been attributed to the outbreak, with the first recorded onset of illness occurring on September 8, 2025. Since then, 1–5 cases have been reported in nearly every calendar week. As of March, some children with S. Bochum infections have continued to experience severe illness.

Children or adolescents aged 2–15 years represent 75 percent (30) of the outbreak patients, with half of these young people (15) being aged 6–12 years, ten aged 2–5 years, and five aged 13–15 years. The ten adult outbreak patients range in age from 21 to 82 years.

One 60-year-old patient died in connection with the outbreak.

Of the 40 reported cases, 18 belong to the same genomic cluster. Genomic sequencing results are still pending for some of the outbreak isolates.

Interviews, case-control study point to chocolate-hazelnut spread

The epidemic curve shows no distinct peak, indicating that a food with a long shelf life could be the source of infection.

To date, 14 outbreak patients (or their parents) have been interviewed. A specific brand of chocolate-hazelnut spread was named by 12 (86 percent) of the interviewees as a food they consumed in the three days before illness onset.

Because baseline consumption frequency of chocolate-hazelnut spreads in the general population is unknown, RKI conducted a case-control study to test the hypothesis that this product was the outbreak source. Cases and suitable non-ill comparison groups (controls) were surveyed using a shortened questionnaire focusing on consumption of various chocolate-hazelnut spreads in the three days prior to illness onset, or prior to completing the questionnaire for controls.

Both cases and controls were limited to individuals aged 2–15 years. Two control groups were used:

• Individuals with other notifiable diseases in the affected districts, primarily interviewed by local public health authorities, and
• Participants from the RKI “Health in Germany” panel, surveyed online.

Controls were selected to match cases by age group and region of residence.

The analysis showed that one specific brand (chocolate-hazelnut spread A) was consumed significantly more often by outbreak cases than by controls. An odds ratio of 93 indicates that individuals who consumed this product had a 93-fold higher likelihood of developing salmonellosis compared to those who did not. Other brands assessed showed no statistical association with illness.

Implicated product recalled

On April 9, the affected chocolate-hazelnut spread was publicly recalled after Salmonella was detected in certain batches during the manufacturer’s internal quality controls.

The investigation is ongoing, including interviews and genomic analyses of Salmonella isolates, as well as additional analyses of food products, manufacturing processes, and supply chains.

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